Field of the Invention
The present disclosure relates to an organic compound with electrochromic properties, an electrochromic element containing this organic compound, an optical filter, a lens unit, an imaging device, and a window component.
Description of the Related Art
An electrochromic element is a device that has a pair of electrodes and an electrochromic layer between the electrodes. By applying voltage across the electrodes, it is possible to adjust the amount of light passing through the electrochromic layer.
Those materials that change their optical absorption properties (colors and optical transmittance) through electrochemical redox reaction are called electrochromic (sometimes abbreviated to “EC” hereinafter) materials. There are a wide variety of EC materials that are known, including inorganic, polymeric, and organic low-molecular weight materials.
Using such materials, EC elements have been applied to equipment such as automotive light-control mirrors and electronic paper. The operation of these kinds of equipment is based on the nature of EC materials: various color tones can be displayed according to the choice of materials. Increasing the range of color tones EC materials can produce will open up the possibility for more widespread use of EC elements.
For example, if EC elements are applied to full-color displays or similar, materials that turn cyan, magenta, and yellow will be needed. Further increasing the range of applications will require increasing the range of color tones EC materials can produce. Stability in coloration and breaching and durability in long and repeated use also need to be improved.
Japanese Patent Laid-Open No. 2007-219272 describes a 3,4′-bipyridine derivative that is colored in its reduced state and an electrochromic element that turns yellow.
International Publication No. WO 2011/046222 describes an organic compound that is classified as a pyridine derivative and is colored in its reduced state. An electrochromic element that turns cyan, magenta, and yellow is also described in this publication.
The 3,4′-bipyridine derivative described in Japanese Patent Laid-Open No. 2007-219272 is a compound that displays a yellow color by absorbing light in the blue spectrum, and the electrochromic element in the same publication contains this compound. For the commercialization of electrochromic elements, the compounds described in these publications alone are not sufficient and more need to be studied.